The ELF computer, which first made its appearance in August 1976 in the Popular Electronics magazine, was a very basic experimenter's board based on the RCA CDP1802 CPU, a rather obscure processor primarily used in embedded systems by the likes of the DOD and NASA. It's main advantage was its simplicity of interfacing and ease of programming. Needless to say that the ELF developed a large following as many hobbyists built their own boards from scratch using the published details in the magazine,
The Heathkit Hero Jr robot came out in 1984 as a more home friendly version of the original Hero 1 robot, but was still equipped with multiple sensors, speech and programming capabilities albeit without a robotic arm attachment. I bought my robot on Ebay and upgraded it with extra memory (24K), an updated ROM, serial communication and a multi-cartridge which combined all of the cartridges produced for the Hero Jr into one master cart, as well as a beefy 10Ah battery and full documentation. The R
This is not a new project which was initially started in 2015, but it was never well documented and I was not very happy with the end result at that time. I picked it up again last month and made significant improvements with some guidance from Tursi, so here it is. Image capture has not been attempted previously on the TI 99/4A computer even though most other contemporary computers did have such a facility developed for them. While I realize that nowadays it's not really necessary since one c
So I've been mulling the idea of creating an X-Y table for my TI computer, which could be used to draw a bitmap image or perhaps do some laser engraving. I searched the web for inspiration and found this ingenious video by HomoFaciens where he uses the stepper platform that moves the laser head in optical drives to create a very effective but small X-Y plotter. https://youtu.be/-XhMT4wXSG4 So I went ahead an found a couple of used DVD-ROM drives on Ebay and ripped them apart, only to find th
I recently came across videos on YouTube showing how to use an arduino to create graphics on an oscilloscope. The basic idea was to use a digital to analog converter (DAC) to convert digital signals from the arduino into analog voltages which could be then fed into an oscilloscope set up in XY mode to create what essentially amounts to cartesian drawings. It certainly looked simple enough conceptually, and I figured I should be able to use the TI 99/4A computer's parallel port to re-create the s
So with the upcoming total solar eclipse on August 21st 2017, I decided to get my hands on a solar filter for my 8" Dobsonian telescope so I can grab some video and pictures of that rather infrequent event. Since I had bought my telescope from Orion, I checked for a compatible solar filter on their site and found out that it was priced at $145! There was no way I was going to pay that much for something like that, and after some thinking decided to create my own. After all it's really a pretty s
So it's time for a new hardware interfacing project for the TI 99/4A, namely a wireless weather station managed by that venerable computer. I think it will be a fun project but likely with a steep learning curve. The goal is to have a functional prototype in time to demo at the 2017 Chicago Fair.
So where does one start? The most obvious would be finding a cost efficient and relatively easy way to achieve wireless communication between the various sensors and the computer. I believe the Xbe
As some of you know, I am constantly experimenting with interfacing the TI 99/A computer to the real world, and I am very fond of using the parallel port for that purpose because it is very easy to interface and program. That said, that kind of use of the parallel port does require low level programming, generally using assembly language, although one could achieve the same thing using either TurboForth or FbForth. This means that you are essentially out of luck unless you know how to program in
Slot car racing sets have always fascinated me, and I have owned a few over the years. Unfortunately, it was always difficult to find opponents to race against beyond just a few runs. I have dabbled many times with the idea of a computer controlled opponent over the years, and finally decided to tackle it as a demo project for the 2016 Chicago International TI Faire in October 2016.
I have a lot of experience under my belt interfacing the TI computer to the real world, using the PIO, joysti
In 2009, I for some reason changed my YouTube user name, and in the process a couple of hardware videos I had under the old name were no longer linked to my newer projects. This bugged me, so I decided to included them here for posterity 1- Light pen for the TI 99/4A computer This was a crude attempt at creating a light pen for the TI given that this machine lacked the necessary circuitry to create an effective one. The solution I came up with is actually pretty simple as detailed in the vide
I am by nature a tinkerer with a wide range of interests, and every year I come up with a variety of projects, whether in hardware or software, most of which nowadays end up on YouTube. Unfortunately, I have rarely documented my thought processes with each project, nor any mistakes I made along the way to completion. So I figured going forward I would start keeping such a blog, if nothing else for my own records, although I suspect that some readers might be interested in some aspects of it.